Robotic vehicles, such as aerial robotic vehicles or “drones,” are often used for a variety of applications, such as surveillance, photography, and/or cargo delivery. Many robotic vehicles use obstacle avoidance systems that work in conjunction with vehicle control systems to avoid hitting people, property, and objects. For example, once a robotic vehicle detects a nearby object, the obstacle avoidance system executing within the controller may prevent the robotic vehicle from approaching the object closer than some minimum distance (which is referred to herein as a “proximity threshold”). The proximity threshold is typically a fixed distance. In the case of aerial robotic vehicles that includes propeller blades, the proximity threshold may be a few feet to avoid damage and/or injury from contact with the spinning propeller blades.